Sealed contact capable of being magnetically actuated

ABSTRACT

A sealed contact for use in electromagnetic relays has an inclined and/or indented contact cover together with an armature having a partial wedge-shaped cross section. The armature in its released state assumes a slanted position, and the electrical contacts are protected from voltage breakdown.

United States Patent Buttel et a1.

[ -Mar. 4, 1975 1 1 SEALED CONTACT CAPABLE OF BEING MAGNETICALLY ACTUATED Inventors: llelmut Buttel, Leonberg-Eltingen;

lngo Rudiger Isert, Bietigheim; Alfred Leicht, Stuttgart-N; Albert Schach, Magstadt, all of Germany Assignee: International Standard Electric Corporation, New York, NY.

Filed: Jan. 24, 1974 Appl. No.: 436,020

Foreign Application Priority Data Feb. 9, 1973 Germany 2306522 u.s. cl. 335/196 Int. Cl. ..H01h 1/12 Field of Search 335/196; 317/615 [56] References Cited UNITED STATES PATENTS 3,150,244 9/1964 Nitsch et al 335/196 3.334.271 8/1967 Bacon, Jr 317/61 5 Primary Examiner-Harold Broome Attorney, Agent, or Firm-John T. OHalloran; Menotti J. Lombardi, Jr.; Richard A. Menelly [57] ABSTRACT A sealed contact for use in electromagnetic relays has an inclined and/or indented contact cover together with an armature having a partial wedge-shaped cross section. The armature in its released state assumes a slanted position, and the electrical contacts are protected from voltage breakdown.

3 Claims, 7 Drawing Figures PATENIEDNAR 4195 saw 1 0f 2 BACKGROUND OF THE INVENTION armature designed as a flat component mounted to the cover by means of an armature holding spring. This contact is described in greater detail in a copending application by W. Mecklenburg et a]. See. No. 417,984, filed Nov. 21, 1973, entitled Magnetically Actuated Sealed Contact," assigned to the assignee of the present invention.

When these contacts are used in electromagnetic relays or other switching devices, which in the closed condition of the contacts, require a plane position of the armature, the armature, upon increasing excitation of the magnetic circuit, first assumes a sloping position before being capable of assuming a plane position. This intermediate sloping armature configuration which exists between the open and closed states of the contacts can be problematic in certain types of switching applications. One particular problem which occurs during the sloping configuration phase of the switching process is voltage flashover at the electrical contact area of the sealed contacts. This flashover damages the electrical contacts sometimes to such an extent that the electrical contacts become stuck in a closed position rendering the sealed contacts inoperative.

The invention, therefore, is based on the problem of providing a sealed contact whose armature, upon magnetically actuating the contact, will immediately as sume a clearly defined plane position on the base plate.

SUMMARY OF THE INVENTION According to the invention this is accomplished by shaping the cover so that the armature meets with its rear portion against the outer part of the base plate and, in the released condition of the contact by prestressing the armature holding spring mounted above the front end of the armature to the cover, the armature assumes an inclined position. By this arrangement the armature, upon magnetically actuating the contact, only has to perform one tilting movement for assuming a plane position on the base plate.

In order for the armature to assume an inclined position in a normal unenergized state it is proposed, in ac cordance with a further embodiment of the invention, that the cover above the rear portion of the armature, is provided with an impression, or that the cover, in accordance with the inclined position of the released armature, is designed to have an inclined shape.

The inclined position of the armature in relation to the base plate produces an ideal voltage breakdown location near the pivot point between the armature and the inner part of the base plate, so that voltage flashover between the contact members is thereby prevented. This ideal breakdown or disruptive path, however, is substantially smaller than the contact spacing. Therefore, in further embodying the invention, it is proposed that the side of the armature facing the outer part of the base plate be provided with a recess of wedge-shaped cross section which, by starting within the range of the armature center, becomes deeper in direction towards the end of the armature. The aforementioned spacing is therefore enlarged to the size necessary for the required flashover voltage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an electromagnetic locking relay with two different sealed contacts facing one another with their base plates, as seen from the side in a partly sectional view;

FIG. 2 shows the relay according to FIG. I in a section taken along the line A-B of FIG. 1;

FIG. 3 shows a further type of embodiment of a sealed contact comprising a flat housing, as seen from the side in a sectional view;

FIG. 4 shows a bottom view of the armature of the contact shown in FIG. 3;

FIG. 5 shows a side view of the armature shown in FIG. 4;

FIG. 6 shows a bottom view of one modified embodiment of an armature for the contact shown in FIG. 3; and

FIG. 7 shows a side view of the armature shown in FIG. 6 as seen from the side, in a section taken along the line C-D of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is shown a locking relay comprising two sealed contacts 1, 2 and which, for example, is suitable for being used as a connector relay in telephone systems. The flat housings of the contacts 1, 2 each consist of a plane base plate and of a hoodshaped cover 3, 4. The rim portion of the covers 3, 4 is firmly connected to the base plate. The base plate of the contacts 1, 2 consists of a ring-shaped outer part 5 and of a disc-shaped inner part 6 which are joined together by means of a glass ring 7. The inner part 6 is arranged eccentrically within the outer part 5. An armature 8 which is designed as a flat component, is mounted to the inside of the cover 3 or 4 by means of an armature holding spring 9 and is thus arranged opposite a section of the inner part 6 as well as opposite a section of the outer part 5.

By correspondinly shaping the cover 3 or 4, the rear portion of the armature 8 is pushed downward to contact the outer part of the base plate. For this purpose the cover 3 of the contact 1 is provided with an impression 10 above the rear portion of the armature 8. A modified type of embodiment shows the cover 4 of the contact 2 to have an inclined design with an additional impression 11 being provided above the rear portion of the armature 8. The armature holding spring 9 is mounted to the cover 3 or 4 above the front end of the armature 8 thus causing by its tension the contact 1, 2 to assume an inclined position when in the released state. As a result of this inclined position the armature 8, upon actuation of the contact 1, 2, only needsto perform one tilting. movement in order to assume a clearly defined plane position on the base plate.

By means of two longitudinally extending incisions, the armature holding spring 9 is subdivided into three fingers of which the outer fingers l2, 13 are connected together by a flat portion 14 to which the armature 8 is mounted (FIG. 2). The middle finger forms a contact spring 15 which, at its free end, carries an electrical contact member 16 made from a good electrically conducting material cooperating with an electrical contact 3'. member 17 as mounted to the inner part 6 of thebase plate. For this purpose the armature 8 is provided with an aperture 18 through which the two electrical contact members 16 and 17 impinge upon one another for making contact. The contact spring can be prestressed with respect to the armature 8.

Between the two base plates of the contacts 1, 2 there are arranged a permanent magnet 19 and an electromagnet which are magnetically coupled in series via the contacts 1, 2. The electromagnet consists of a magnetically conductive pin 20 and of a magnetizing winding 21, and is applied to the oppositely arranged inner parts 6 of the contacts 1, 2. The permanent magnet 19 is arranged next to the electromagnet with each of its poles facing the oppositely arranged surfaces of the outer parts 5 of contacts 1 and 2. The inner parts 6 are each provided with soldering lugs 22, and the outer parts 5 are each provided with soldering lugs 23 for connecting electrical terminals to the contacts 1, 2.

In the described contacts 1 and 2, both the force of the armature holding spring, and the contact spacing can be adjusted on the finished contacts, in that the cover, e.g. 3, of the contact 1 is indented at the points (a), (b) or (c), with the aid of a tool. An indentation at point (a) will increase the tension of the armature holding spring 9 with respect to the cover 3. A flat indentation at point (b) will reduce the contact spacing. An indentation at point (c) reduces the tension of the armature holding spring 9 with respect to the cover 3. These supplementary adjustments permit greater tolerances during manufacture of the contact.

In FIG. 2 there is shown the relay according to FIG. 1 by way of a section taken along the line A-B. The embodiment of the armature holding spring 9 or contact spring 15 has already been described hereinbefore. The reference numerals 24 indicate the mounting points for the armature holding spring 9 on the cover 3, and the reference numerals 25 indicate the mounting points for the armature 8. The remaining reference numerals are identical to those of FIG. 1. The armature holding spring may be attached to the cover, and the armature may be attached to the armature holding spring by a variety of methods, for example by welding, riveting, cementing and the like.

FIG. 3 shows one complete embodiment of a flat contact. From the drawing it can be seen that the inclined armature 8, in its release position, is positioned very close to the inner part 6 of the base plate. This creates a voltage breakdown path between the armature 8 and the inner part 6 near the pivot point of the armature which is substantially smaller than the spacing between the contact members 16 and 17. The location of this breakdown point is advantageous for avoiding a voltage flashover between the contact members 16 and 17. In order to enlarge the distance between the' inclined armature 8 and the inner part 6 of the base plate to the size required for the most favorable flashover voltage, the armature 8 has on its surface facing the outer part 5 of the base plate, a recess 26 of wedgeshaped cross section beginning near the armature center and gradually becoming deeper toward the end of the armature. This size is still considerably smaller than that of the contact spacing, so that voltage flashover is reliably prevented from taking place at the contact members 16, 17. During adjustment of the contact after its completed assembly, and within the vicinity of the contact-making point, the ideal breakdown spacing is only slightly reduced. In this manner the flashover voltage will not be affected by the adjustment.

Two different embodiments ofthe wedge-shaped recess 26 of the armature 8 are shown in FIGS. 4 to 7. In the case of the armature shown in FIGS. 4 and 5, the recess 26 extends transversely along the entire width of the armature. In the case of the armature 8 as shown in FIGS. 6 and 7 the recess 26" is a form designed to have the shape of a circular segment. The reference numeral 18 indicates the apertures through which the contact members 16, 17 (FIG. 3) pass in order to contact each other.

While we have described above the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

l. A sealed contact of the type capable of being magnetically actuated and having a flat base plate including an inner and outer part joined by a glass seal, a cover of predetermined shape sealed to the base plate, an armature holding spring fixedly attached to the cover wherein the improvement comprises an armature fixedly attached to the armature holding spring said armature having a wedge-shaped cross sectional recess along a part of its length on the surface of said armature adjoining the outer part of said base plate, said recess having a deepest edge toward the pivot point formed between said armature and said base plate, and gradually decreasing in depth toward the opposite end of said armature, whereby a voltage breakdown path is provided between said armature and said base plate.

2. A sealed contact according to claim 1 wherein said recess extends transversely over the entire width of said armature.

3. A sealed contact according to claim 1 wherein said recess has the shape of a circular segment. 

1. A sealed contact of the type capable of being magnetically actuated and having a flat base plate including an inner and outer part joined by a glass seal, a cover of predetermined shape sealed to the base plate, an armature holding spring fixedly attached to the cover wherein the improvement comprises an armature fixedly attached to the armature holding spring said armature having a wedge-shaped cross sectional recess along a part of its length on the surface of said armature adjoining the outer part of said base plate, said recess having a deepest edge toward the pivot point formed between said armature and said base plate, and gradually decreasing in depth toward the opposite end of said armature, whereby a voltage breakdown path is provided between said armature and said base plate.
 2. A sealed contact according to claim 1 wherein said recess extends transversely over the entire width of said armature.
 3. A sealed contact according to claim 1 wherein said recess has the shape of a circular segment. 